Memory is one type of integrated circuitry, and is used in computer systems for storing data. Integrated memory is usually fabricated in one or more arrays of individual memory cells. Additional integrated circuitry may be formed on a common die as one or more memory arrays, with such additional integrated circuitry often being formed peripherally to the memory arrays so that it does not interrupt repeating patterns within the memory arrays. The additional circuitry may be configured for any of numerous applications. For instance, the additional circuitry may be configured to read and/or program the memory arrays.
Memory arrays may be highly integrated, and accordingly formed to very small pitches. In contrast, peripheral circuitry may be less highly-integrated than the arrays, and accordingly formed to larger pitches than the circuitry of the memory arrays.
It may be desirable to form interconnects to integrated circuitry of a memory array, while simultaneously forming interconnects to integrated circuitry in a region peripheral to the memory array. In some applications, it is desired to remove material from between tightly-spaced components of a memory array prior to forming the interconnects, and to protect the periphery with an etch stop during such removal to avoid damage to the peripheral circuitry. The etch stop is patterned to be over the periphery and not the array, and such patterning may be accomplished utilizing a photolithographically-patterned mask. However, the formation and utilization of such mask adds complexity to a fabrication process, which increases costs and introduces risks of mask misalignment. It would therefore be desirable to develop new methods of patterning an etch stop to be over a periphery region and not a memory region which avoid utilization of the photolithographically-patterned mask. It would be further desirable for such methods to be suitable for formation of etch stops in other applications in which an etch stop is to be selectively formed over a less highly-integrated region relative to a more highly-integrated region.